Such vessel exchange trucks are used to transport metallurgic vessels with worn brick linings, for example, from the vessel stand to a brick lining stand, and back. To this end, it is necessary to detach the vessel from its rigging. The rigging in metallurgical plants consists of many different configured items including tilting frames, annular supports, pivot arms, casting devices, and the like. The transport of the vessel takes place on rails which cross. The carriage frame is lifted off the track at crossings, turned by 90.degree., and replaced on the other track. The present invention uses for this purpose pistons located in the center of the carriage frame for engaging the ground. While lift pistons, arranged at the carriage ends, are well known, the latter, however, require a long stroke as the carriage together with the vessel must be lifted up to operating position of the vessel.
Mounts for the metallurgical vessel vary greatly. The type of mounts on which the invention is based requires a lift table lifting the vessel into guides which have become untrue due to the heat of operation, or due to wear and tear. The lift table adapts to the inaccuracy by means of the mentioned inserted ball-and-socket joints, and/or traction elements articulated by means of ball-and-socket joints.
It has been disclosed in U.S. Pat. No. 3,718,265 to balance these inaccuracies by an individual adjustment of the lift table according to height and incline by arranging at each corner of the rectangular carriage frame lift devices in pairs, bearing Cardan or universal joints, at the ends of which the cylinders are attached, and by additional Cardan joints provided at the traction elements forming a connection with a bridge carrying the vessel. In this design, the traction elements may shift in the form of a parallelogram, whereby the lift devices maintain their perpendicular position. While the adaptability of the two spaced bridges forming the support for the lift table meets the requirements desired in operation, the system of the "bridge" leads to a relatively great structural width and structural length of the vessel exchange truck. The usual vessel exchange truck, therefore, necessitates a wide rail track which is abnormal.
The present invention provides vessel exchange trucks which are equipped with compact lift devices for a flexibly arranged lift table, as well as in view of the arrangement of the joint system for the lift table. The carriage is more narrow than before and runs on tracks of normal width. It is lighter and, with minor structural changes, may be used for small or large metallurgical vessels.
This problem is solved by the truck of the invention by first determining the plan outline of the vessels to be supported, and positioning the piston-cylinder units providing the lift for the lift table around the circumference of the plan outline. In addition, the guiding elements which provide traction for the lift table are hinged thereto and extend below the table a length equal to the piston-cylinder units. The guiding elements are hinged, in turn, at their lower ends to intermediate elements extending from the area of the support bearing surface of the vessels to be supported, and rigidly connected thereto.
Accordingly, the invention provides lift devices arranged closer than usual to the center of the vessel exchange truck. This arrangement in the center under the vessel ordinarily would lead to a very high structure. This problem is solved by the invention by means of the mentioned intermediate elements forming a stiff connection with the bearings, and to which the traction elements are hinged. This hinged arrangement extends into recessed areas of the carriage frame and is a decided saving in structural height. The use of traction elements whose cross section can receive great tractive or tensile forces, contributes to diminish the structural width.
The length of the traction elements is at the same time a way of increasing the adaptability of the support bearings to a warped vessel surface. In the sense of a greater adaptability, longer traction elements have the effect of increasing the horizontal displacement movement of the lift table. The vessel exchange truck of the invention is built in compact form in conjunction with the divided arrangement of the piston-cylinder units and traction elements and by using relatively small cross sections, as well as using the length of the traction elements. The compact construction provides a smaller width so that exchange truck can run on the normal track width of a conventional metallurgical plant rail track. Furthermore, due to the construction by the invention, there are considerable savings in weight and this construction is suitable for large as well as for small metallurgical vessels.
In further development of the basic concept of the invention, the intermediate elements consist of supports extending downward from the lift table, and are coordinated with the piston-cylinder units which are arranged spaced around the circumference of the lift table. Favorably, the lengths of the intermediate elements match approximately the lengths of the traction elements so that a considerable saving in structural height is achieved. Furthermore, the stress on the intermediate support element is manifested as buckling stress, and the stress on the traction element is manifested as tensile stress. Thus, the piston rods of the piston-cylinder units are only subject to tensile stress. Such piston-cylinder units are less expensive, and less heavy for longer piston travels.
The intermediate elements or links according to this invention are arranged so that the supports extending down from the lift table are of forked design. One piston-cylinder unit each is arranged within the space embraced by the fork. This arrangement also represents a saving in the truck's structural height.
Another modification of the positioning system of the invention is that the intermediate elements consist of yoke-shaped U-frames resting on the joint housings of the piston rods. This provides a two-way flexibility for the lift table support or the bearing points forming the lift table so that an even better adjustment to the contact points is reached when inserting the vessel. The invention presupposes that the lift table is elastically deformed under the load of the vessel which may amount to several hundred tons. This deformation may very easily be compensated for on account of the twofold flexibility. This adaptability to the insertion of the vessel into the bearing surface of the lift table is increased when sufficient space is left between the U-shaped frames of the intermediate elements and the related joint housing of the piston rod to allow play therebetween. The independence of individual bearing points can also be cancelled by providing a rigid interconnection between all U-frames by means of rods in the shape of a polygon.
For vessels whose rigging is provided at two opposing sides on the vessel circumference, it is advantageous if the piston-cylinder units are arranged with the intermediate elements at the longitudinal sides of the carriage forming entrance openings.
Another arrangement of the lift device and/or the guiding system of the invention is that the lift elements, flexibly attached to the intermediate elements, are hinged at their upper ends to a cross rail on a guide column displaceable within a guide housing and located centrally of the lift device. This arrangement also guarantees not only a narrow construction of the vessel exchange truck, but also the desired horizontal displacement of the lift table and/or its bearing points in an area of approximately 30-70 mm. The guide column, displaceable within a guide housing, may consist of a piston-cylinder unit. The structural height of the lift table is furthermore reduced when the guide column, which is displaceable within the guide housing, consists of a telescopic piston-cylinder unit.
According to further details of the invention the traction elements themselves may consist of piston-cylinder units with the cylinder housing and the piston rod each provided with a ball-and-socket joint. For the guiding system which, according to the type described, only results in a horizontal displacement motion of the lift table in the area of about 30 to 70 mm, and for such steering systems according to the invention for which a dual adaptation flexibility is considered advantageous, provision is made that the bearings supporting the metallurgical vessel consist of short-stroke piston-cylinder units arranged on the lift table and/or the U-frames coordinated with the piston-cylinder units.
Furthermore, an extremely low structural height of the vessel exchange truck is achieved by providing the interior frame portion with vertical recesses for the intermediate elements extending down from the lift table and/or piston-cylinder units.
Examples of the invention are shown on the drawings and explained as follows: